function s1_generate_a_series_of_files(){
	for i in {1..100}; do
		echo "$i" > "/tmp/new_file$i"
	done
}
function s2_list_4_files_in_long_format_about_account_and_group(){
	files=("/etc/passwd" "/etc/group" "/etc/shadow" "/etc/gshadow")
	for file in "${files[@]}"; do
		ls -l "$file"
	done | sort
}
function s3_find_items_related_to_given_username(){
	grep -h $1 /etc/{passwd,shadow} |sort -d
}
function s4_find_items_related_to_given_group_name(){
	local group_name=$1
	local files=(/etc/group /etc/gshadow)
	for file in "${files[@]}"; do
		grep -h "^$group_name:" "$file"
	done | sort
}
function s5_create_groups_for_given_group_names(){
	local groups=("rnd" "itoperation")
	for group in "${groups[@]}"; do
		groupadd "$group"
	done
}
function s6_create_users_and_set_their_group_as_required(){
	users=("adam" "bob" "calvin" "david" "edward")
	primary_groups=("users" "users" "users" "users" "users")
	supplementary_groups=("rnd" "rnd" "itoperation" "itoperation" "rnd")

	for i in "${!users[@]}"; do
		useradd -g "${primary_groups[$i]}" "${users[$i]}"
		useradd -aG "${supplementary_groups[$i]}" "${users[$i]}"
	done
}
function s7_change_users_shell(){
	users=("adam" "edward")
	for user in "${users[@]}"; do
		usermod -s /usr/bin/sh "$user"
	done
}
function s8_set_password_change_policy(){
	local usernames=("adam" "bob" "calvin" "david" "edward")
	for username in "${usernames[@]}"; do
		chage -M 60 -m 10 -W 10 "$username"
	done
}
function s9_set_password_for_five-users(){
	usernames=(adam bob calvin david edward)
	for i in $(seq 1 5);do
	echo ${usernames[$((i-1))]}
	echo $i
	done
	echo "${usernames[0]}:$1" | chpasswd
	echo "${usernames[1]}:$2" | chpasswd
	echo "${usernames[2]}:$3" | chpasswd
	echo "${usernames[3]}:$4" | chpasswd
	echo "${usernames[4]}:$5" | chpasswd
}
function s10_lock_bobs-password(){
	usermod -L bob
}
function s11_include_adam_into_wheel_group(){
	usermod -a -G wheel adam
}
function s12_change_files_permission(){
	for i in {1..33}; do
	file="/tmp/new_file$(expr 3 \*$i)"
	chmod 640 "$file"
	done
}
